1. Field of the Invention
The present invention relates to a syringe adapter with a ball-typed valve, especially to a syringe adapter that allows a needleless syringe to inject liquid medicine therethrough.
2. Description of the Prior Art(s)
In order to reduce needle shots for patients undergoing medical examinations like a blood test, a syringe adapter is mounted on a delivery pipe of an intravenous bag or mounted directly on the patient. By so doing, nutrition or liquid medicine can be injected into the patient through the syringe adapter and the patient does not have to go through the discomfort of repeated injections.
A conventional syringe adapter, such as a BI-DIRECTIONAL VALVE AND METHOD OF USING SAME (U.S. Pat. No. 5,782,816) or a FLUID HANDLING DEVICE AND METHOD OF MAKING SAME (U.S. Pat. No. 7,520,489), has a dosing tube and a resilient valve. The resilient valve is mounted in the dosing tube. The resilient valve has a peripheral protrusion formed around the resilient valve and abutting an inner surface of the dosing tube to securely seal the open ends of the dosing tube when the conventional syringe adapter is not in use. Thus, when a needleless syringe is inserted into the dosing tube, the resilient valve is pressed and arced, so a flowing space is formed between the resilient valve, the open ends and the inner surface of the dosing tube. Then, liquid medicine is injected into a patient through the conventional syringe adapter.
However, the conventional syringe adapter has the following disadvantages. When the needleless syringe is drawn out from the syringe adapter, a negative pressure causes the blood of the patient or the liquid medicine to flow back to and remain in the conventional syringe adapter. Consequently, when injecting again, the blood and the liquid medicine remaining in the conventional syringe adapter is injected back into the patient's body, putting the patient at the risk of infection. Furthermore, air remaining in the dosing tube is also injected into the patient's body. The patient's blood vessel is expanded by the air, causing patient discomfort.
Another conventional syringe adapter, such as a NEEDLELESS ACCESS DEVICE (U.S. Pat. No. 6,228,069), has a tubular body, a cap mounted on and around the body, and a plunger and a spring mounted in the body. The plunger is pulled by the spring and selectively seals an open end of the body. A channel that allows the liquid medicine to flow through and a vent that allows the air in the body to flow out of the conventional syringe adapter are defined between the body and the cap so the air is not injected into the patient's body.
Since the plunger is pulled by the spring, at least four elements for assembling the abovementioned conventional syringe adapter are needed. Thus, manufacturing cost of the conventional syringe adapter is high and manufacturing processes of the conventional syringe adapter is complicated. Moreover, since the metal spring affects the result of a magnetic resonance imaging (MRI) scan, the patient cannot wear the conventional syringe adapter during a MRI check-up. In that case, the intended effect of the conventional syringe adapter, that is, reducing the needle shots for the patients, is not achieved.
To overcome the shortcomings, the present invention provides a syringe adapter with a ball-typed valve to mitigate or obviate the aforementioned problems.